Stabilizer for silver halide light-sensitive material

ABSTRACT

A stabilizer for photographic silver halide materials, consisting of an acidic aqueous solution containing ammonium thiocyanate, and an aluminum compound, characterized by incorporation therein of (1) a sulfite and (2) an aliphatic aldehyde or aliphatic ketone of one to five carbon atoms.

United States Patent 11 1 1111 3,802,883 Ohkubo et al. Apr. 9, 1974 STABILIZER FOR SILVER HALIDE 3,238,043 3/1966 Levy 96/61 3,326,684 6/l967 Nishio et al 6/61 LIGHT SENSITIVE MATERIAL 3,352,682 1 H1967 Harris et al. 96/95 [75] Inventors: Kinji Ohkubo; Katsumi Hayas 3,525,567 8/1970 Levine 96/61 both of Kanagawa, Japan 3,630,737 12/1971 Kairies 96/61 [73] Assignee: Fuji Photo Film Co., Ltd.,

Kanagawa. Japan Primary E.\'aminerJ. Travis Brown Assistant Examiner-M. Kelley [22] Ffled' June 1971 Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, [2]] Appl. No.: 151,961 Zinn & Macpeak [30] Foreign Application Priority Data June 10. 1970 Japan 45-49635 [57] ABSTRACT A stabilizer for photographic silver halide materials, [52] US. Cl. 96/61 R, 96/5(C);R, 96/95 Consisting of an acidic aqueous Solution containing [51] Int. Cl G03c6S/38, 03c 1/06 ammonium thiocyanate and an aluminum compound [58] Field of Search 96/61 l 48 OP characterized by incorporation therein of l) a sulfite and (2) an aliphatic aldehyde or aliphatic ketone of [56] References cued one to five carbon atoms.

UNITED STATES PATENTS 3,212,895 10/1965 Barbier et al. 96/6l 11 Claims, No Drawings STABILIZER FOR SILVER HALIDE LIGHT-SENSITIVE MATERIAL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a stabilizing solution for silver halide photographic materials. Generally a photographic processing of silver halide material consists of four steps, i.e., development, fixing, stopping and water washing. Various treatments have hitherto been proposed to speed up the processing steps.

2. Description of the Prior Art Among them stabilization processing is more practical. Stabilization processing means a method in which an exposed photographic silver halide material isdeveloped and immersed in an aqueous solution containing a stabilizing agent, illustrated hereinafter, whereby to convert the non-developed silver halide remaining in the emulsion layer into a silver complex salt stable to light. By this stabilizing treatment, the water-washing treatment, after thefixing, which requires a relatively long time, can be omitted and, consequently, rapid treatment of a photographic silver halide material is made possible.

Stabilzing agents used in the stabilizing treatment ar mentioned in detail in H. D. Russel and E. C. Yacke: Stabilizing Treatment of Films and Printing Papers, PSA Journal (Photo. Sci. Tech), 16B 59 (1950). As stabilizing agents ordinarily alkali metal and ammonium thiocyanates are used. I

When an alkali metal thiocyanate or ammonium thiocyanate is used as a stabilizing agent, there is the advantage that the speed of stabilization is high. However, the following disadvantages are unavoidable in this case.

One disadvantage is that a photographic material stabilized by such stabilizing agents is sticky, so that handling thereof after processing is inconvenient. This phenomenon would be due to the fact that alkali metal or ammonium thiocyanates are deliquescent and have the property of softening the gelatin used as a binder of a silver halide emulsion layer.

Another disadvantage is that a photographic material stabilized by such stabilizing agents tends to show a lowering or vanishing of image density when stored for a long period of time. For example, the color of a black image tends to vanish or discolor in yellow during storage for a long period of time. This phenomenon is called fading. The fading appears often when a stabilized print is stored under high humidity.

In order to get rid of the sticky property of a stabilized print itis proposed in US. Pat. No. 2,453,347 to add a hardener, such as, formaldehyde, glyoxal, potassium alum or chrome alum to the stabilizing solution.

In accordance with our investigation, it is found that aluminum compounds, such as, potassium alum (aluminum potassium sulfate) are the most effective to reduce the sticky property of a stabilized print, because the aldehyde type hardener does not show a sufficient hardening effect, within an acidic pH region, to stop development by the stabilizer, and chrome alum has the disadvantage of contaminating a print.

in order to prevent the image fading of a stabilized print, it is well known to add an alkali metal or ammonium sulfite, bisulfite or metabisulfite to a stabilizing solution. (Japanese Patent 540,299)

Preparation of a stabilizer having both a hardening action and an image fading inhibiting action, in addition to a stabilizing action on the silver halide, by using the above-mentioned techniques in combination, encounters the following difficulties.

The first is that the aluminum ion is stable at a pH of 6, or less, but forms a precipitate of aluminum hydroxide at a pH of more than 6. The second is that the ability of aluminum to harden a gelatin is maximum at a pH of about 3. The third is that sulfite is stable at a pH of more than 4, but decomposes at a pH of 4 or less, and the decomposed product contaminates the print. That is to say, the pH region is very narrow wherein both are stably coexistent. The fourth is that a stability enhancing agent, such as, boric acid cannot be used. Since a conventional acidic fixing solution of thiosulfate, wherein an aluminum compound and sulfite are coexistent, is unstable and liable to precipitate, a stability enhancing agent, such as, boric acid is often added to the fixing solution. However, addition of this agent to a stabilizer containing an aluminum compound and a sulfite improves the stability thereof, but lowers markedly the hardening action. The fifth is that an aqueous solution .of thiocyanate, which pH is low, tends to corrode stainless steel used for processing machines.

It is one object of the invention to provide astabilizer such that a print stabilized thereby does not show a sticky property.

It is another object of the invention to provide a stabilizer such that when a print stabilized thereby is allowed to stand under high temperatures and high humidities, fading of the image hardly takes place.

It is another object of the invention to provide a stable stabilizer such that no precipitation and no decomposition occur even after storage for a long time. Other objects and advantages of the invention will be apparent from the following description.

We the inventors have found that the abovementioned objects can be accomplished by adding an aliphatic aldehyde or aliphatic ketone and a sulfite to a stabilizer containing ammonium thiocyanate and aluminum compound. 1

Compounds havingcarbon atoms of up to five are preferably used, such as, aliphatic aldehyde or aliphatic ketone, for example, formaldehyde, acetaldehyde, glyoxal,'glutaraldehyde, acetone and methyl ethyl ketone.

It is known that an aldehyde or ketone is added to bisulfite ion in aqueous solution to thus form a bisulfite adduct. The aliphatic aldehyde or aliphatic ketone may directly be added to a stabilizer containing a sulfite to form an adduct in the solution or may be added to a stabilizer in the form of a bisulfite adduct. The addition amount of aliphatic aldehyde or ketone used according to the invention must be sufficient to form an adduct with sulfite added to a stabilizer and at least equimolar with the sulfite. Moreover, aldehydes and ketones may be used in admixture.

As the aluminum compound of the invention there may be used any water-soluble compound containing aluminum, for example, potassium alum, aluminum sulfate or aluminum chloride.

Illustrative of the sulfite of the invention are sodium sulfite, sodium bisulfite, potassium sulfite, potassium metabisulfite and ammonium sulfite. in the invention, sulfite bisulfite and methbisulfite.

The ability of aluminum to harden a gelatin film is the greatest in a range of pH 3-4. A stabilizer containing ammonium thiocyanate and an aluminum compound and having a pH of 3-4 has a marked hardening effect, but a print image stabilized thereby tends to discolor and corrosion occurs remarkably on stainless Steel satires Activator sodium hydroxide 58 g sodium sulfite (anhydrous) 23 g potassium bromide 0.4 g

to l000 ml water Then, it was stabilized in the following stabilizing solution for seconds:

A B C' D ammonium thiocyanate 200 g 200 g 200 g 200 g sodium acetate (trihydrate) 52 g 52 g 52 g 52 g glacial acetic acid 88 g 88 g 88 g' 88 g aluminum chloride l 25 g 25 g 25 g (hexahydrate) sodium bisulfite 52 g 52 g 52 g formalin (37% aqueous soln.) 50 g 50 g water to I000 ml ti'ra'6raprosmg' maaiine to wliich this stabilizer adheres.

in a range of pH 3-4, sulfite is unstable and decomposes directly, but, as is evident from the above illustratioii, an adduct with an aliphatic aldehyde or ketone is stable in this pl-l region, the combination of the adduct stable and not corrosive and has strong hardening ability.

Aluminum ion reacts with various ions in aqueous solution often to form a precipitate. For example, when a stabilizer containing ammonium thiocyanate and aluininur'ri sulfate is allowed to stand at 0C for one week, crystals of aluminum ammonium sulfate are deposited. Addition of a tartrate, such as, potassium tartrate or sodium tartrate or Rochelle salts to a stabilizer containing ammonium thiocyanate and aluminum compound in a proportion of 0.1-2 g/l prevents deposition of crystals.-

One kg of a gelatino-silver chlorobromide emulsion consisting of 105 percent by weight of gelatin and 4.9% by weight of a silver chlorobromide containing 5 the] percent of silver bromide and a trace of silver iodide was melted and kept at 3550C, to which an ortho-. sensitizing dye and stabilizer were then added. The pH was adjusted to 5.1 and g of hydroquinone was added in the form of a solid adequate agitation. The emulsion was coated onto a baryta paper with the addition of a hardener followed by dr ing.

The thus obtained printing paper was exposed and developed in an activator having the following composition for 3 seconds:

l with an aluminum compound give a stabilizer that is TABLE 1 Stabilizing solution A B C D Stickiness of print high low low low Image density on print 2.01 L98 2.05 2.05 directly after processing After 5 hrs. at 30C and 1.78 0.39 1.00 1.80

% RH whiteness good good bad good (yellow) The properties of the stabilizer are shown in Table 2.

TAB LE 2 Stabilizer A B C D Color colorless colorless yellow colorless Immersion of not not not not stainless steel (SUS27) for one day corroded corroded corroded corroded As is evident from the above results, a stabilizer which has a hardening capacity, but shows little image fading, and does not corrode stainless steel, can be obtained by the combined use of an aluminum compound,

and sulfite adduct.

EXAMPLE 2 consisting of 1 15 percent by weight of gelatin and 5.3 percent by weight of silver chlorobromide containing 15 mol percent of silver bromide was melted and to this melt an orthosensitizing dye was added. The pH was adjusted to 5.0, the temperature was kept at 40C and 12 g of hydroquinonewas added with adequate agitation. It was then coated onto a baryta paper without adding a hardener, followed by drying.

The resulting printing paper was exposed and developed in an activator having the following composition for 3 seconds:

Activator The properties of a stabilized print are shown in Table One kg of a gelatino-silver chlorobromide emulsion Then, it was stabilized in a stabilizer having the following composition for seconds:

Stabilizer ammonium thiocyanate 200 g sodium acetate (trihydrate) 50 g glacial acetic acid 70 g aluminum potassium sulfate 80 g (IZ-hydrate) potassium metabisulfite 66.5 g glutaraldehyde 70 g l-phenyl5-mercaptotetrazole 50 ml (05% methanol) water to L000 ml The stabilized print showed no stickiness and, even after storage for a long time, no lowering of image density. When a piece of stainless steel (SUS27) was immersed in the above stabilizer for one day, it was not corroded.

EXAMPLE 3 In Example 2 the stabilizer was substituted by the following solution:

Stabilizer ammonium thiocyanate 250 g sodium acetate (trihydrate) 42 g glacial acetic acid 18 g aluminum sulfate (IS-hydrate) 54 g Rochelle salts 2 g adduct salt solution 290 ml 2-amino-5-mercapto-l ,3,4-thiadiazole 80 ml (0.5% methanol) water to [000 ml aluminum chloride, characterized by incorporation therein of l a sulfite and (2) an aliphatic aldehyde or aliphatic ketone of one to five carbon atoms, the pH of said stabilizer ranging from 3 to 4,

said aliphatic aldehyde or ketone being present in an amount sufficient to form an adduct with the sulfite added to the stabilizer and being present in at least an equimolar amount with the sulfite.

2. The stabilizer as claimed in claim 1 wherein said aliphatic aldehyde is formaldehyde, acetoaldehyde, glyoxal or glutaraldehyde.

3. The stabilizer as claimed in claim 1 wherein said ketone is acetone or methylethyl-ketone.

4. The stabilizer as claimed in claim 1 wherein said sulfite is sodium sulfite, sodium bisulfite, potassium sulfite, potassium metabisulfite or ammonium sulfite.

5. The stabilizer as claimed in claim 1 wherein said stabilizer contains a tartrate.

6. The stabilizer as claimed in claim 5 wherein said tartrate is sodium tartrate, potassium tartrate or potassium sodium tartrate.

7. The stabilizer as claimed in claim 5 wherein the amount of said tartrate is 0.1 2 g per one liter.

8. The stabilizer as claimed in claim 1 wherein said stabilizer contains a heterocyclic mercapto compound.

9. The stabilizer as claimed in claim 8 wherein the amount of said mercapto compound is at least 0.01 percent by weight based on ammonium thiocyanate.

10. The stabilizer as claimed in claim 8 wherein said mercapto compound is 2-mercaptoimidazole, 2- mercaptobenzimidazole, 2-mercaptobenzotriazole, 2- amino-5-mercapto-1,3,4-thiadiazole or l-phenyl-S- mercaptotetrazole.

11. A method for rapidly processing an exposed silver halide photographic emulsion layer containing a developing agent therein which comprises treating the layer with an aqueous alkali solution, and stabilizing it with an acidic aqueous solution containing (1) ammonium thiocyanate, (2) a water-soluble compound containing aluminum selected from the group consisting of potassium alum, aluminum sulfate, and aluminum chloride, (3) a sulfite and (4) an aliphatic aldehyde or aliphatic ketone of one to five carbon atoms, the pH of said acidic aqueous solution ranging from 3-4,

said aliphatic aldehyde or ketone being present in an amount sufficient to form an adduct with the sulfite added to the stabilizer and being present in at least an equimolar amount with the sulfite. 

2. The stabilizer as claimed in claim 1 wherein said aliphatic aldehyde is formaldehyde, acetoaldehyde, glyoxal or glutaraldehyde.
 3. The stabilizer as claimed in claim 1 wherein said ketone is acetone or methylethyl-ketone.
 4. The stabilizer as claimed in claim 1 wherein said sulfite is sodium sulfite, sodium bisulfite, potassium sulfite, potassium metabisulfite or ammonium sulfite.
 5. The stabilizer as claimed in claim 1 wherein said stabilizer contains a tartrate.
 6. The stabilizer as claimed in claim 5 wherein said tartrate is sodium tartrate, potassium tartrate or potassium sodium tartrate.
 7. The stabilizer as claimed in claim 5 wherein the amount of said tartrate is 0.1 - 2 g per one liter.
 8. The stabilizer as claimed in claim 1 wherein said stabilizer contains a heterocyclic mercapto compound.
 9. The stabilizer as claimed in claim 8 wherein the amount of said mercapto compound is at least 0.01 percent by weight based on ammonium thiocyanate.
 10. The stabilizer as claimeD in claim 8 wherein said mercapto compound is 2-mercaptoimidazole, 2-mercaptobenzimidazole, 2-mercaptobenzotriazole, 2-amino-5-mercapto-1,3,4-thiadiazole or 1-phenyl-5-mercaptotetrazole.
 11. A method for rapidly processing an exposed silver halide photographic emulsion layer containing a developing agent therein which comprises treating the layer with an aqueous alkali solution, and stabilizing it with an acidic aqueous solution containing (1) ammonium thiocyanate, (2) a water-soluble compound containing aluminum selected from the group consisting of potassium alum, aluminum sulfate, and aluminum chloride, (3) a sulfite and (4) an aliphatic aldehyde or aliphatic ketone of one to five carbon atoms, the pH of said acidic aqueous solution ranging from 3-4, said aliphatic aldehyde or ketone being present in an amount sufficient to form an adduct with the sulfite added to the stabilizer and being present in at least an equimolar amount with the sulfite. 